Harsh words for a delicate looking spring plant, but garlic mustard is no innocent. It's near the top of almost every list of invasive herbs in New England. The Divisions of Fisheries and Wildlife, Mass Audubon, The Nature Conservancy, the National Plant Conservation Alliance—all are sounding alarms on this plant, particularly now, when garlic mustard is easily identifiable and before it disperses its prolific seed arsenal.
Prolific and toxic
A single plant is capable of producing thousands of seeds, viable for more than five years. Because it can self-pollinate, it takes only one plant to wreak havoc on gardens, roadsides, and even woodlands, in just a few years.
As if garlic mustard's reproductive prowess isn't enough, the herb also produces allopathic chemicals—plant toxins—that destroy essential soil fungi that make nutrients available to most plants, including trees and shrubs. Garlic mustard's capacity to inhibit the growth of other plants, combined with its ability to grow in both sun and shade, allows it to colonize not just roadsides, but also woodland floors, where it displaces understory wild flowers like spring beauty, wild ginger, and trillium.
Deer don't like the plant and will eat more of the remaining plants the mustard is displacing, further hastening their demise. A variety of caterpillar is poisoned when it mistakes the invasive mustard for the noninvasive one it normally feeds on.
What to look for
A biennial, garlic mustard stays close to the ground its first year, forming a rosette of rounded leaves that are easy to mistake for other plants. The second year it takes off and up, creating tall, thin stems topped with tiny white flowers. The leaves become paler, more heart-shaped, and have distinctly serrated edges. When crushed, the leaves smell like garlic.
Masses of these second-year plants were easily visible along roadsides in town earlier in the month. Now, the flowers are going by and the plants are devoting their energy to producing seeds in long, very thin pods on slender two- to three-foot stems.
Pull it and bag it
In its native Europe, garlic mustard has natural predators and the soil fungi there are immune to its toxic effect, but here, if it is to be checked, we humans will have to become the predator.
Getting rid of small patches of garlic mustard is easy. Just pull it up. The ease with which garlic mustard comes out, roots and all, makes it a satisfying weed to pull. But it shouldn't be left around where the seeds can mature. Mass Audubon recommends storing the pulled plants in a black plastic bag, which should be left in the sun for several weeks to destroy the seeds.
Or eat it
Rich in vitamins A and C, garlic mustard is thought to have arrived on Long Island in the 1860s for culinary use. According to Russ Cohen of the Massachusetts Department of Fish and Game, who is also a wild foods expert, the first-year leaves can be parboiled and eaten like spinach. To use second-year plants, Cohen recommends stir-frying the stems and flowers or adding them to soups. The young leaves can replace basil in pesto recipes and the roots used as a substitute for horseradish.